The CSP Cancer Surveillance Core (Core B) provides outcome identification for the three field projects (A, B, C) in this Program Project. This Core relies on the infrastructure of the Cancer Surveillance Program (CSP), which is the population-based SEER cancer registry for Los Angeles County. Two of the projects (A and B) depend on population-based rapid case ascertainment (RCA), for ovarian cancer and non-Hodgkin's lymphoma, respectively, which is a major function of this Core. Project C requires linkages with the cancer registry to find incident breast cancers in a large cohort of teachers. We believe the efficiency of RCA by this Core exceeds that of any other population based cancer registry nationally. RCA activities include the identification of all new cases through regular screening of pathology reports at all facilities where cancer is diagnosed. For patient reports qualifying for ongoing studies (currently totaling about 13,100 reports annually) a minimal data set is abstracted by CSP Field Technicians. The average interval from date of pathology to the date that the pathology report is delivered to the study investigator is about 4 weeks. The registry identifies about 37,000 incident cancers annually in Los Angeles County (LAC) and has over 1 million incident cases in its master file, accumulated since its inception in 1972. Given the demographic diversity of LAC, these data provide a rich resource for studying cancer patterns.